High-modulus, high-tenacity, low shrinkage polycarbonamides made by the intermolecular condensation of linear diamines containing from 6 to 10 carbon atoms with the linear dicarboxylic acids containing from 2 to 10 carbon atoms and specifically designed for industrial uses are sold under the trademarks DuPont High Tenacity Nylon (6-6) and Cordura.RTM. nylon in which the filaments have been texturized and bulked becoming disarranged, looped and tangled within the bundle to give the Cordura yarn a degree of bulk equal to that of spun yarns. Fabrics made of these yarns are stable against light and heat, have low dry heat shrinkage (3%), are fatigue resistant with good adhesion properties, have high-tenacity with outstanding toughness and resistance to degradation, and are designed for specific industrial uses such as coated fabrics, protective fabrics, sewing threads, tapes, backpacks, boots, camera bags, golf bags, hand bags, horse blankets, hunting apparel and gear, indoor/outdoor furniture, luggage, shoes, protective covers, ski covers/boot bags, sportbags/totes/duffles, upholstery, video/computer bags, wallets, and apparel.
A serious problem limiting the commercial exploitation of these high-modulus, high-tenacity, low-shrinkage polyamide fibers has been the fact that fabrics made of these fibers are difficult to efficiently and economically dye in practice and produce level dyed fabrics with good overall fastness properties especially to light and washing. Initially, these polyamide fabrics have been dyed in dyeing machines such as jigs, beams, pad rolls, or high temperature, atmospheric and/or pressurized steamers. These dyeing operations are time consuming, difficult to control in practice, and are therefore inefficient and costly in producing first quality dyed goods.
Accordingly, it is an object of the present invention to provide a continuous dyeing process for the coloration of fabrics made of high-modulus, high-tenacity, low-shrinkage polyamide fibers. Another object of the invention is to provide a method in which fabrics made of high-modulus, high-tenacity, low-shrinkage polyamide fibers can be economically and efficiently continously thermosol dyed with acid dyes to obtain colored fabrics with superior overall fastness properties, without having to use high temperature steamers. Another object of this invention is to provide a process in which these polyamide fabrics can be dyed under conditions and with conventional processing equipment, that does not require special modification or adjustment--equipment that is also suitable for the continuous dyeing of other textile fabrics such as polyesters and polyester blends. Other objects of the invention will become apparent from a consideration of the description which follows.